The present invention relates to a vehicle seat belt retractor which has a tension reducing mechanism for increasing the comfort of a vehicle occupant having a seat belt associated with the retractor extending across the occupant.
A known seat belt retractor has two springs for biasing a seat belt webbing storage spool to rotate in a belt winding direction relative to a retractor frame. The two springs are connected in series with a ratchet wheel interposed between the two springs. One end of the first spring is fixed relative to the retractor frame and the other end is attached to act on the ratchet wheel. One end of the second spring is attached to the ratchet wheel and the other end is attached to act on the spool.
The retractor has a comfort mechanism actuatable to block rotation of the ratchet wheel in the belt winding direction relative to the retractor frame. When the comfort mechanism is actuated only the spring force of the second spring is applied to bias the spool in the belt winding direction. Thus, a reduced tension is placed upon the seat belt webbing as compared to when both springs act to bias the spool in the belt winding direction. The reduced tension in the seat belt webbing increases the comfort of the vehicle occupant.
If movement of the vehicle occupant necessitates that additional seat belt webbing be withdrawn from the spool, such additional seat belt webbing is provided by rotation of the spool in a belt withdrawal direction. The ratchet wheel commonly also rotates in the belt withdrawal direction. If a ratchet blocking pawl remains engaged with the ratchet wheel, a clicking sound produced by the teeth of the ratchet wheel engaging the pawl will occur upon rotation of the ratchet wheel in the withdrawal direction.